With a background as a hugely successful book series by one of Iceland’s top crime writers, Ragnar Jónasson, The Darkness was always going to be a highly anticipated screen adaptation. Add in a top director, big-budget backing from international studios, and the recipe looks almost perfect. It’s a surprise, therefore, to find that the end result is something less than its constituent parts promise.

It all starts promisingly – monochrome title sequence, car headlights in the winter darkness of Reykjavik and the surrounding beautiful Icelandic countryside, underscored by a haunting instrumental score that could almost be from page 1:01 of How to Open a Nordic Noir TV Series. It nods to many of the most successful outings of the genre.

It also starts with a bang – a pedestrian is deliberately mown down on the snowy Reykjavik streets. As Detective Inspector Hulda Hermannsdóttir arrives on the scene, the young driver claims it was an accident and that the man walked out of nowhere, a story at odds with the reality we’ve just witnessed.

Hulda may wonder why a senior detective is tasked with a traffic accident, but it’s endemic of the issues she’s facing. On the verge of retiring at the end of a successful career, albeit one with challenges, she’s being pushed towards the exit door in favour of a younger, male replacement. Cases handed to her are far beneath her skill set, hastening her exit.

When a young woman’s body is found frozen in a glacier, the seasoned detective has something more suitable to investigate: the road traffic accident, one of many threads soon abandoned. The arrival of a British detective, returning to the Iceland of his birth, provides Hulda with a counterpoint – a detective unburdened by the prejudices and assumptions that her longer-serving colleagues harbour.

It soon becomes apparent that there’s more to this case than simply a hitchhiker falling into a glacier, and when a second young woman goes missing, it looks like there is a potential serial killer on the loose.

So far, so good – a blueprint for classic Nordic Noir: a troubled detective, an outsider coming to terms with a new culture, serial killers, and internal conflict within the investigative team. Add in the stunning backdrop of Iceland itself, the brooding darkness of the Arctic night and driving snow, and it’s a powerful, evocative mix.

So why doesn’t it quite work when on paper it should?

The first puzzling production choice is to film the series in English instead of the native Icelandic. With CBS as producers, there’s probably an eye on the international market, but the choice robs the series of some of its authenticity. It is an authenticity further dented by an English script that at times sounds as though it has been run through translation software, resulting in clunky dialogue that proves a barrier to engagement rather than a script to draw us into a thrilling storyline.

The international theme is further continued by the mainly Icelandic cast being supplemented by English actors. In the case of Lucas, the British policeman working in Reykjavik, it works well. Jack Bannon’s portrayal is perhaps the most detailed of the production, coming to terms with both a challenging investigation alongside his own personal struggles. Even so, the material leaves gaps, making it hard to fully engage with Lucas – his Icelandic backstory merely hinted at, his sexuality clearly a matter of conflict but only partly explored.

Douglas Henshall’s inclusion is less successful. The use of an English actor for an Icelandic character is one of many puzzling questions in this production.

Árni Lárusson’s Bjartur is a more fully developed role and one of the highlights of the series. A man with links to the Icelandic criminal underworld, somewhat at odds with his day job as a teacher, it’s a beautifully portrayed view of light and shade.

That leaves us with the central character of Hulda Hermannsdóttir herself. It is arguably here the biggest problem lies. Author Ragnar Jónasson paints Hulda as a suitably complex character, the original book series playing out in reverse chronological order across her career.

Like any good Nordic detective, Hulda is a haunted character – here in The Darkness still trying to come to terms with the suicide of her teenage daughter. Seen as something of a relic of an older style of policing by her colleagues, the sexism and ageism she faces is blatant, but Hermannsdóttir sticks to her own path.

It’s a challenging character to portray, and one that actress Lena Olin seems to struggle with. Emotions come and go, and that’s fine with a character struggling with turmoil, but it makes for a performance hard to engage with. Large sections of script are delivered flat, with an almost poker-faced expression, occasionally punctuated by explosive outbursts. Olin turns in a theatrical performance, the largesse more a vehicle to project emotion over a large stage than suited to the intimacy of the camera.

Olin’s husband, Lasse Hallström, directs, and while he clearly has an eye for the visual – the piece looks stunning, with atmospheric cinematography – he struggles with pace and clarity. Subplots and themes are introduced and then discarded, pace veers from glacial to action-packed, and the requisite tension needed in a good Nordic Noir never materialises.

The action-packed finale is somewhat unsatisfactory, with decisions made by Hulda hard to credit with authenticity. It ends with a cliffhanger and many unresolved questions – but by that point the viewer may have given up interest.

The Darkness is by no means a disaster – there’s much to enjoy – but the prevailing question remains: why? There’s much potential in The Darkness, but something isn’t right in the mix. If Hulda is to return to transfer her literary adventures on screen, some major revisions are needed for season two.

The Darkness is now showing on Channel 4 On Demand